Method and arrangement for high-frequency telephony



H.-H. SCHOTANUS A. STERINGA ID ZERDA. METHOD AND ARRANGEMENT FbRflIGI-IFREQUENCY TELEPHONY Filed May 7) 192;

Asa consequence of these frequency-variations, when used for wirelesstelephony, the antenna will, as lon as sounds strike' the microphoneradiate t e energy in diflferent, varying frequencies and the energypicked up by the receiving system will vary with the frequency of thesoundwaves.

Numerous variations in the above indicated arrangements are possible.The invention is not llmited to wireless telephony, but can equally beapplied for highfrequencytelephony or -telegraphy ,on wires.

The principal advantages of the invention are:

1. A common microphone can be used, even for relatively high values ofthe energy.

2. Modulation in, sound-frequency, the emitted energy remainingconstant.

I 3. The transmitted sounds are not distorted as is the case if atransformer is used.

4. Economical working because one triode can be used, whereas almost allother systems need two triodes.

5; For the same amount of radiated energy the range is much larger thanfor any other system.

6. The connections and operating are very simple.

7. Losses are reduced considerably because the microphone absorbspractically no energy and causes no damping.

As a result from "a large series of tests can be stated .that withsending apparatus according to the invention 30 watts in an antenna ofan approximative height of feet and a length of approximately 120 feetare sufiicient to cover about 250 miles. Speech and music aretransmitted very clearly.

For the same distance in other systeins about 600 watts are necessary,whereas, by

the use of two and more vacuum tubes, the

primary energyoften amounts to 2000 watts. The same way of connectingcan be used for telephony, ,or for telegraphy with undamped waves; themicrophones can be shortcircuited.

Instead of'an open antenna or a loop antenna, an ordinary telephone linecan be used for the transmission of the highfrequency raphy.

Having fully described my invention, what I I claim is:

1. A high frequency valve telephone transmitter, having a grid circuittuned to the energy transmitting circuit, said comprising a'microphoneshunte by an unpedanoe, consisting of a capacity and an inductance.

2. A high frequency valve telephone transmitter having a grid circuittuned to the energy-transmitting circuit, said grid circuit comprising amicrophone and a shunt for said microphone constituted by an inductance.

3. A high frequency valve telephone transmitter having a grid circuittuned to the energy-transmitting circuit, said grid circuit comprising amicrophone and a shunt for said micro hone constituted by a capacity.

4. A- hig frequency valve telephone transmitter having a grid circuittuned to the energy-transmitting circuit, said grid circuit comprisingacondenser and two inductances, one of said inductances being connectedin series with the microphone.

5. A high frequency valve telephone transmitter having a grid circuittuned to the energy transmitting circuit, said grid circuit comprising amicrophone connected intermediately between suitable inductances andcapacities whereby the current reaching the microphone, must firsttraverse said inductances and capacities.

6. A high frequency valve telephone transmitter having a grid circuittuned to the energy transmitting circuit, said grid circuit comprising amicrophone connected intermediately between suitable inductances andcapacities "whereby the current reaching said microphone must firsttraverse said inductances and capacities and an additional impedanceshunting said microphone.

In testimony whereof I have aflixed my signature.

HANSO HENRICUS SCHOTANUS i STERINGA IDZERDA.

id circuit

